PolyKybd Firmware (QMK fork)

This repository is a fork of QMK that hosts the firmware for PolyKybd — a split mechanical keyboard with a small OLED display under every keycap. The PolyKybd-specific firmware lives at keyboards/polykybd/; the rest of the tree is upstream QMK, kept so the customisations can ride on QMK's build system, HID stack and ChibiOS RP2040 port.

Project progress and hardware info:

• Hardware & build log: github.com/thpoll83/PolyKybd
• Support the project: ko-fi.com/polykb

What is PolyKybd?

PolyKybd runs on a Raspberry Pi RP2040 with 8 MB of external QSPI flash. It is a split keyboard (left + right halves over UART) with up to 72 per-keycap OLED displays (72×40 px monochrome) plus a 128×64 status OLED. A companion host application, PolyKybdHost, tracks the active window and pushes per-app overlays, language layouts and icons to the keycaps over a custom 64-byte HID report protocol.

Variants

Two hardware variants share one firmware (the shared logic lives in keyboards/polykybd/poly_keymap.c):

• split72 — 72-key, RGB matrix, Cirque trackpad, 128×64 status OLED (actively developed).
• split42 — 42-key CRKBD-footprint variant (formerly corne42, renamed 2026-06).

Building

The full keyboard documentation is in keyboards/polykybd/readme.md. In short, replace <variant> with split72 or split42:

qmk compile -kb polykybd/<variant> -km default
# or
make polykybd/<variant>:default

The .uf2 is for manual bootloader-drive recovery; the deliverable for flashing over HID via PolyKybdHost is the raw .bin (arm-none-eabi-objcopy -O binary .build/polykybd_split72_default.elf out.bin).

Related repositories

Repo	Role
thpoll83/PolyKybd	Hardware design (PCB, case, schematics)
thpoll83/PolyKybdHost	Host application — overlay/window tracking, firmware updater
thpoll83/polykybd-ctnd	Hardware-in-the-loop test & deploy station / CI runner
thpoll83/polykybd-docs	Project documentation site

Upstream QMK

PolyKybd is built on QMK, the Quantum Mechanical Keyboard Firmware, which is based on the tmk_keyboard firmware. QMK's documentation lives at docs.qmk.fm, and QMK is developed and maintained by Jack Humbert of OLKB with contributions from the community and Hasu. All upstream QMK keyboards and features remain in this tree; only keyboards/polykybd/ and a handful of supporting build hooks are PolyKybd-specific.